


Bonding Time

by dementeddesires (lewdboy55)



Category: New Dangan Ronpa V3: Everyone's New Semester of Killing
Genre: Alternate Universe, F/M, Pseudo-Incest
Language: English
Status: Completed
Published: 2021-01-30
Updated: 2021-01-30
Packaged: 2021-03-16 09:34:54
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,566
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29080203
Author URL: https://archiveofourown.org/users/lewdboy55/pseuds/dementeddesires
Summary: Shuichi gets adopted by the Shirogane family. Tsumugi wants him to feel welcome, and coddles him to give him the affection he never had. Maybe...coddles him a bit too much.
Relationships: Saihara Shuichi & Shirogane Tsumugi
Comments: 3
Kudos: 8





	Bonding Time

**Author's Note:**

> It's me again. It's also 3 am aha...anyways I hope you all enjoy this one. Gimme criticism/requests and don't hold back! I want to sharpen my skills and give you all some good reads!

“Y’know you’re a lucky kid, getting adopted not even a few days after being put up for a adoption.” The driver spoke to Shuichi. The driver worked for the adoption center that Shuichi was placed in, after his parents were charged with neglect. They had made Shuichi live alone in a small apartment as they lived overseas in a luxurious mansion. They claimed a “hands off” approach would ensure Shuichi would make in in the real world, but this only further damned them and essentially proved neglect. Hell, it showed they encouraged it. “Prolly is cause yer parents got big bucks. Yer prolly gonna be a famous one, bein the result of an actor and screenwriter fuckin’.” The man chuckled and Shuichi just pulled down his cap more. “Ah, shit my bad kid. It’s fucked up what they did to ya. Anyways here ya are.” The driver stopped and Shuichi looked out the window. 

The house looked pretty average, the windows near the top of the house suggested more than one floor and the lawn was trimmed and nice. It was in the suburbs and it seemed pretty quiet and ordinary. A lot nicer than his apartment. Once he got outside with his luggage, the driver honked. “Good luck kid! Don’t fuck it up!” Shuichi watched the driver speed off and was glad he wouldn’t have to deal with such a loud an arrogant man again. Rolling his luggage to the door, he rang the doorbell. 

An older man opened the door and looked down. “Ah, Shuichi Saihara! Welcome home my boy!” The man held Shuichi tight, causing him to get embarrassed and tense up. The man noticed and slowly let go. “Ah! Sorry, sorry. My name’s Ryoto Shirogane, you don’t gotta call me dad or pops.” The man gave a soft smile. Shuichi just bowed. “A-A pleasure to meet you, Mr. Shirogane.” Shuichi replied in a shaky voice. Ryoto stood to the side and motioned for Shuichi to come in. “Nice to meet you too Shuichi. Want me to help with your luggage?” Shuichi shook his head no at the question and went inside. 

The interior looked nice, several paintings hung around the house, as well as some family photos. It had a very calming and welcoming feel, which felt a bit strange to Shuichi. It reminded him of the homes of some sitcoms he used to watch when he was younger. “Upstairs and to your right. Should be across from my daughter’s room. Your new sister. Her name is Tsumugi Shirogane. She can be very.... excited about the stuff she likes but I think you two will get along. You guys are the same age too!” Ryoto smiled and Shuichi nodded. “I see...” Shuichi replied softly and went straight to his room. “Let me know if you need anything!” Ryoto called out as Shuichi closed the door behind him. 

Shuichi began to unpack and put his clothes away. The room was light blue, with a tv mounted on the wall. His closet was pretty big, which was pretty unnecessary considering the small amount of clothes he had. He had his own bathroom right next to his room, and began to put his toiletries away there. Once he finished unpacking, he began to lay down on the bed. He slowly sunk into it, surprised by its softness. It was a lot comfier and nicer than his old bed. A lot bigger too. Slowly, he ended up closing his eyes and fell asleep. 

Shuichi awoke to knocking on his door. He sat upright and partly opened it. “Hi, big brother! I’m your little sister, Tsumugi! Although...you’re a bit shorter than I thought! Maybe I’m the older sister?” She giggled softly. Shuichi blushed and looked down, using his cap to hide his head. “I think we’re the same age. We are in the same age... I was born September 7.” Tsumugi then snapped her finger. “I’m older! August 15! So, you have to call me big sis Tsumugi!” she smiled. “Oh, you need help with anything little brother?” Shuichi shook his head no. “Oh...okay. Um, well dinner Is ready so come down when you can okay?” Shuichi nodded. Tsumugi took a step back and quickly left. Shuichi went to the bathroom and washed his hands, then went down for dinner. 

Shuichi sat down at the table and took off his hat, then saw the food being served, then noticed Ryoto’s wife isn't here. Ryoto served Shuichi steamed fish with some rice. It looked better than most of the convenience store bentos he ate at home. It certainly tasted better as well. “Thank you, it’s very good.” Shuichi spoke once he swallowed some food. Tsumugi and Ryoto smiled. “Glad to hear it. Oh, I should mention that I’ll be out all day to pick Yuki up from the airport.” Ryoto spoke. Tsumugi’s eyes shone. “Yay! W-wait but why all day?” Tsumugi asked. “Ah well we got a lot of errands to run after. She mainly needs to go around and get stuff. Not even jet lag can stop her.” Ryoto chuckled. “This can be a good time for you two to bond! Get to know each other more.” Ryota looked to Shuichi, who was now almost done with his food. Shuichi glanced up and then looked away a bit. “Y-yeah...” He replied sheepishly. Tsumugi pouted and went behind Shuichi holding him tight. “C’mon little brother, you gotta be more enthusiastic than that! I’m gonna make sure you feel welcome!” Tsumugi giggled. Ryoto chuckled and Shuichi just blushed brighter. “I-I’m done with my food...please let go.” Tsumugi let go and Shuichi quickly put his dishes away and bolted to his room. “He’s a shy one, isn't he?” Ryoto sighed. “Well, I just hope he knows we do care about him.” 

Tsumugi went upstairs after finishing her food and washing the dishes, knocking on Shuichi’s door. He opened, now dressed in some black pj’s. “You look cozy, and you also made me do the dishes all alone. Help your big sis next time.” She pouted, and Shuichi bowed deeply. “I-I’m sorry, I promise to do them next time.” Tsumugi didn’t expect such a sincere answer, and instead just sighed and patted his head. “You need to relax a bit, Shuichi. I’m not that mad. Besides, I wanted to talk. So, may I come in?” Shuichi stepped to the side and let her in. And Tsumugi noticed his cheeks turning a shade of red over the sudden pat. She sat down on his bed and patted next to her. “Sit here.” 

Shuichi took a seat next to her and looked down, doing all his could to avoid eye contact. “I want to get to know you more. I know it’s pretty sudden, to suddenly be thrown into the family and I don’t expect you to immediately call me big sis or to call dad dad or mom mom,. I don’t expect you to suddenly open up, but I do want you to at least feel a bit comfortable around us. My parents told me about your situation and... well I don’t truly understand how you feel, I want you to know that I am here for you if you need me. To talk about problems or your pains or anything. I won’t be able to solve your problems, but I’ll always listen anyways.” Tsumugi smiled softly and held Shuichi close to her. “Rely on your big sis okay? I’ll be here for support!” Shuichi froze for a bit, taking in her words. Words he had never heard told to him, words that he secretly longed and craved. “...why are you being so nice to me?” Shuichi asked, thinking there might be some ulterior motive. Tsumugi held him a bit tighter. “I want you to feel welcome here. To feel like you belong and you are a part of us. I don’t want you to feel neglected. Not anymore. Big sis is always here for you.” Shuichi stayed silent for a bit, then began to sob softly into her chest, shaking as he did. Tsumugi ran her hands along his back, trying to calm him. “Just let it out. Let it out...” Tsumugi whispered softly into his ear. 

Shuichi would cry into her for a long while, slowly calming down as his breathing slowed. “Sounds like you needed that, huh?” Tsumugi said softly, gently running her hands along his head. “Y-yeah...thank you. Sorry I-” Tsumugi cut Shuichi off. “No, don’t apologize. You did nothing wrong. Just take some deep breaths. IF you want, we can watch some anime! I know a few good ones.” Tsumugi reached for the remote and turned on the TV. “Anime usually cheers me up after a long cry.” Tsumugi then put on an anime. Shuichi slowly lifted his head up and looked into her eyes. She looked down at him and had a soft smile. “Anything you had in mind?” She asked. He shook his head. “N-not really...but what's the show about?” He looked at the tv, it seemed to be in the middle of an episode. Tsumugi smiled softly. “Well, it might take a while but I can explain if you want!” Shuichi nodded. “that would be nice. Thanks...big sis.” 

Tsumugi explained the entire plot as the episode went on and Shuichi ended up getting pretty interested. She then switched to a streaming service and they binged the first season but fell asleep halfway through the second, with Shuichi resting his head on Tsumugi’s shoulder and Tsumugi resting her head on Shuichi’s head. It took Shuichi’s phone alarm to wake them both up, groaning and rubbing their eyes. “I-It’s a Saturday...why do you have an alarm on a Saturdayyy?” Tsumugi pouted and Shuichi turned it off. “I usually wake up early on Saturdays to get breakfast. Early bird specials.” Shuichi stretched and Tsumugi checked her phone. “It’s 6 am. C’mon go back to sleeeep!” Tsumugi looked over at Shuichi, her arms open to him. He blushed and pointed to his door. “I’m gonna get dressed. You should too. Your...I-I mean our dad will be leaving soon, won’t he?” Tsumugi slowly got up and yawned. “Mmm...good point. It would be a nice surprise to see dad out. Good thinking little brother!” Tsumugi smiled and stumbled sleepily to her room. Shuichi got dressed in black pants and a black shirt, then went down to see Ryoto off. 

When he went downstairs, there was a note on the table. “If you’re reading this, I have left to pick up mom. It’ll probably be lunch time when Tsumugi wakes up, and if it isn't then good job Shuichi on getting her up early for once! There should be enough ingredients for pancakes, and you’re in charge of making them for leaving Tsumugi to do the dishes! I left some money on the table for lunch and dinner. Stay safe! From, Dad.” Shuichi put down the note and sighed. “Well, better get started...I just hope I don’t burn anything.” 

Tsumugi checked her phone and saw her dad sent her a text that he had left at 5:30, so she immediately jumped into her bed and fell asleep when she went to her room. It was only when she heard a knock on her door that she begrudgingly wakes up. “C’mon Shuichi lemme sleeep. Dad already leeeeft!” Tsumugi whined. “I know. I made pancakes. Open the door so I can give them to you.” Shuichi replied. “Is it okay if I open the door?” Tsumugi smirked. “S-shuichi! I’m indecent though! U-unless you don’t mind seeing your big sister all vulnerable and... exposed.” She spoke in a shy, bashful tone that mimicked some cliché anime scene. This worked and Shuichi was bright red and flustered. “N-no sorry I-I-I'll give you privacy s-sorry!” Shuichi took a step back from the door and turned around. “Should I l-” He was cut off when the door opened. “My my, what a good brother you are for turning around, Should I hug you? I’m not very covered though...” Shuichi stiffened and Tsumugi could swear she saw his ahoge almost stand upright for a second. She giggled and placed a hand on his shoulder. “Kidding! I’m not nude. Turn around!” Shuichi let out a sigh and turned around, holding a tray with pancakes and coffee. 

“It looks and smells delicious! Thank you! What about yours though?” Tsumugi asked. “I’ll just make another batch for myself. I wanted yours done first.” Shuichi then proceeded to walk away, but Tsumugi called out to him. “Actually, why don’t we continue the anime in my room and share the pancakes? It’s honestly a bit too much.” Shuichi turned around. “I only brought one fork and knife though, and one cup of coffee...” Tsumugi had a simple answer for a simple problem. “We can share them!” 

Shuichi sat down on Tsumugi’s bed next to her, covers over their legs as they watched the anime and shared the pancakes. They would pass the knife and fork between each other, until Tsumugi began to cut another piece. “Open up!” Tsumugi brought the fork with pancake jabbed in it near Shuichi’s mouth. “I-I’m not a k-” Shuichi was interrupted as Tsumugi timed it just right so that the fork entered Shuichi’s mouth, making him have to chew and eat it. She then cut herself a piece and ate. “It’s more efficient this way. Besides, I always wanted a brother to coddle!” She giggled and cut another piece for Shuichi. “Be a good boy and open up!” Shuichi’s face went crimson red as he slowly opened his mouth and ate. “Aww you’re so adorable!” Tsumugi giggled. She noticed some syrup fall down from Shuichi’s lip and cleaned it with a napkin. “I... know you’re trying to make up for all of the affection I never had. I appreciate it but, I don’t want you to feel as if you have to. Besides, I’m not a little kid.” Shuichi spoke, his voice more firm than usual. He thought Tsumugi would be offended by what he said, but she just smiled instead. “Haha...you saw right through me huh? Am I that obvious?” Shuichi shook his head. 

“I’m a good detective. My uncle taught me a lot about reading people and solving cases. Besides, I had assumed you would be overly affectionate when you told me your parents told you about my past. I’m not bothered by it, but I’m not twelve you know.” Shuichi gently patted Tsumugi’s head. “I do appreciate it though. It makes me happy knowing you are trying.” Tsumugi grabbed Shuichi and brought his head to her chest, holding him tight. “I made you happy! Yes! You’re opening up!” She giggled as Shuichi struggled to breathe in his comfortable, soft suffocation. Tsumugi let go as Shuichi gasped for air. “S-sorry, I got a bit excited. Although I didn’t know you were a detective! That’s so cool! In fact,...you kinda look like this one character from an anime I saw a while back...” Tsumugi squinted her eyes and Shuichi tilted his head. “I just solved some missing pet cases. Nothing major.” Tsumugi nodded and moved the tray aside, placing it on the floor and brought out her phone. “I think I cosplayed a gender bent version of them. Oh, I cosplay by the way! I have some sponsors and I’m doing pretty good in the biz so far! Here are some cosplays I’ve done!” 

Shuichi looked at her phone then at Tsumugi. He did this a few times for every cosplay Tsumugi showed off. “H-how...how do you look so different?! I mean, there is no way you can make your body change so sudde-” Tsumugi interrupted him almost immediately. “Makeup, binders, silicone, EVA foam, wigs, if there is something you wanna cosplay you find a way to make it work! I dedicate a lot of time to this, so I do all I can to make it perfect!” Tsumugi giggled. “Although I do hate using binders. My breasts tend to hurt. Especially for flat chested characters.” She sighed, and gently patted her breasts. “I’m sorry girls, never again shall we do Megumin. It was too painful...” Shuichi didn’t get it but figured it must’ve been a pain. He swiped right a few times to see more of her cosplays. “They’re really impressive! I don’t even want to know how long all these costs to make!” Shuichi looked to Tsumugi, and she had a proud smile on her face. “Well, I make it all myself, and I usually make back the cost thanks to sponsors so it works out!” 

Shuichi was even more impressed. “All by yourself?! You made all of them?!” Tsumugi nods with even more pride. “Yes sir! It’s my passion after all! It’s worth it one hundred percent to make them perfect! Want to see one of my latest cosplays?” She asked excited. Shuichi nods and Tsumugi went to change. It took some time but she eventually emerged as a schoolgirl with a very short skirt and a top that revealed some of her cleavage. She did a cute pose and winked. “Haiiiiii Shuichi-kuuuuun! It’s been, like, forever ago since we met!” Shuichi blushed, she went full gal, getting fully immersed into the role. “T-tsumugi?” He asked. Tsumugi looked around. “Ehhh? Your sis isn't here! It’s me!” She then walked over to Shuichi, but ended up tripping and falling down with a thud. Shuichi got up and went to check on her. “A-are you okay?!” 

Tsumugi rubbed her head. “Y-yeah...sorry I get carried away sometimes when I cosplay..aha...” Tsumugi slowly stood up, with Shuichi helping her. “It’s impressive how well into character you get. You look amazing too.” Tsumugi blushed and smiled. “Awww thank you! You sure you aren’t saying that cause this is a bit more revealing?” She teased. Shuichi blushed and glanced away. “I-I’m saying it because I think you can make any cosplay work. Revealing or not, you look amazing regardless!” Tsumugi blushed and gently patted Shuichi’s head. “My my, aren’t you good with words!” Shuichi smiled and let her, her soft hand on his head felt nice. “Maybe one day I can get you to cosplay!” Tsumugi giggled. Shuichi tilted his head in thought. “Hrmm maybe.” 

“I’m gonna shower and we can keep watching anime after, okay?” Tsumugi walked to her bathroom. After some time, “H-Hey um...can you help me Shuichi?” Tsumugi called and Shuichi went to the bathroom door. “What is it?” He called. “I um...forgot to bring my clothes and a towel so...can you bring them? Any towel is fine, but for clothes bring me the pink box.” She responded. Shuichi tilted his head. “Wait...pink box?” Tsumugi sighed. “Yeah, pink box. I separate cosplay clothes and regular ones in boxes with different colors. Pink is for regular and blue is cosplay! There are others that are other colors but that’s just random props and stuff. Don’t open any of them though! A girl likes privacy!” Shuichi didn’t get it, but he wouldn’t argue. “It’s under my bed! Just don’t open it!” Hearing this made Shuichi want to open the box when he did find it. “Why is it under your bed?” He asked. “My closet has too much space! Also, there should be a towel in that pink box too!” Shuichi scratched his head. “Well...okay.” 

Shuichi went back to her room and looked under her bed. She had several different boxes with different colors under there. “Red....orange...black...ah pink!” He pulled out the pink one and picked it up, bringing it to Tsumugi. He knocked on the door and Tsumugi opened it just a bit. “Good little brother! Close your eyes.” Shuichi did that heard the door close, then opened his eyes. He did wonder...what exactly was in that box? Or the other boxes? He went back to her room and thought for a bit. It was wrong to go through someone’s stuff, but then again why are these boxes so hidden? His curiosity got the better of him and he opened the red one. 

Shuichi’s face got bright red, he saw cat ears, a butt-plug tail, along with some lewd neko-themed underwear. “W-woah...” Shuichi quickly put those away as well as the box. Was...everything in these boxes so lewd?! He checked the orange one, and it had a leash, several vibrators, a ball gag, along with rope. “W-what the actual hell...she is one insane cosplayer. Or pervert.” Shuichi put that one away and all the others he took out, but a hand on his shoulder stopped him. Shuichi’s heart dropped as he felt her glare into the back of his head. “Little brother...I think I told you NOT to open the other boxes.” 

Shuichi immediately turned around and bowed deeply, his head touching the floor as he apologized profusely. Tsumugi was silent, eventually getting on her knees and running her hands along his hair, then tugging it. “I really should kill you, bring you back to life, kill you again and bring you back to life again over and over like some sadistic witch until you’re utterly and completely broken.” Shuichi gulped, and Tsumugi just pouted. “I won’t though. On one condition, I’ll forgive you.” Shuichi spoke before he could think. “Whatever it is I accept!” Tsumugi giggled and gently ran her hands along his head. “Cute. I didn’t even explain what it was. My condition, that you accepted, is to let your big sister take care of you, Sweetchi.”. 

Tsumugi was dressed in a silky robe, purple with a floral design. Her robe showed off one of her legs and was liberal about showing her cleavage. She extended a hand to Shuichi and he accepted it, slowly standing up. She then pushed Shuichi onto the bed and slowly got on top of him, kissing him from his neck up to his lips. “W-wait...aren't we doing this too fast? G-going too far?” Shuichi asked, his heart racing as his mind and body fought one another. “I think it’s just right Sweetchi. Besides, we need more bonding time, so I think we can bond our best by truly loving each other in the purest way possible. This is a lot like my favorite visual novel, except I get to try the real thing except a toy. Not only that, but I am truly in love with the man in front of me. My Sweetchi.” Tsumugi slowly pressed her lips against Shuichi. His mind slowly began to melt, his lust slowly overtaking him as he relaxed and gave in. He kissed her back deeply, holding her close as they shared a deep and lustful kiss. 

Tsumugi slowly pulled away from the kiss and began to remove his shirt, nearly ripping it off his chest. She placed small kisses on his chest, licking it and looking up at him seductively. Slowly she reached her hands down and undid his pants, pulling them down along with his underwear, her hands fondling his growing erection. She looked down and bit her lip. “You’ve got a pretty good friend here Sweetchi. I like how he looks and feels. I think he should meet some friends too.” Tsumugi slowly loosened her bathrobe and tossed it aside. She then began to shake her large breasts at him, winking. “You like them? All natural, all for my Sweetchi.” She winked. Shuichi at this point was as erect as he could ever be, panting softly and needily. “I love them, and I want them.” Tsumugi giggled and slowly kissed down to his shaft. “First things first...” 

Tsumugi sandwiched his erection between her breasts and began to softly massage it, moving them up and down as Shuichi moaned softly. “Feel good Sweetchi? Don’t you love it when big sis Tsumugi takes gooood care of you?” She teased, then gently kissed his tip. Shuichi’s cock throbbed and he gripped the bedsheets. “Y-yeah, it feels so good big sis, it feels like heaven!” Shuichi moaned out, his panting getting heavier. Tsumugi smirked and began to swirl her tongue around his tip, moving her breasts a bit faster and rubbing her nipples for stimulation. “M-more...” Shuichi needily begged as Tsumugi pleased him. She slowly moved her breasts away and began to go down his shaft, slowly sucking on him as she went deeper and deeper down. “O-oh my God this feel amazing...” Shuichi moaned, his hand on Tsumugi’s head as he pulled her deeper and deeper down until she was at his base. Tsumugi sucked as hard as she could, swirling her tongue and gagging on him for his pleasure. Shuichi couldn’t handle it after some time, and climaxed down her throat. His hands gripped her head tight as his legs shook a bit, his eyes rolling to the back of his head. Tsumugi’s eyes widened at the sudden release, but swallowed it up and slowly bobbed her head, cleaning his erection and made a popping noise as she moved away from his cock. 

Shuichi was taking deep and heavy breaths, laying down. Tsumugi licked her lips. “Thank you for the meal, Sweetchi. Although I think it’s time that I continue to take care of you. After all, you’re still so stiff for your big sis.” Tsumugi slowly began to stroke Shuichi, making sure to get every last drop out and to lick it up. Then, she mounted him and began to slowly grind on his shaft. “W-wait shouldn't we use protection?” Shuichi asked, a bit worried. Tsumugi grinned and winked. “I’m on the pill. Besides, I want our love to be natural.” Shuichi nods. “Then let’s do it.” Tsumugi slowly guides Shuichi into her entrance, then moves down slowly on him, gasping and moaning as he enters her. 

“I-it’s so big...so good...just...perfect...” Tsumugi slowly moves her hips down and up, going faster and faster with each bounce. Shuichi slowly sat up and began to suckle on her breasts, moaning softly and holding her tight. “G-good boy Sweetchi! Suck on these breasts like it’s the yummiest in the world!” Tsumugi moans louder and presses his head against her breasts. She slowly lays down, bringing Shuichi on top of her, letting him take control. Shuichi thrusted deep and hard as he kept sucking and nipping her breasts, licking her stiffened nipples. Tsumugi wrapped her legs tight around Shuichi, locking him in. “I-inside! Release it all inside me please Sweetchi!” Tsumugi climaxed and shivered, moaning his name loudly as drool slowly came down from the side of her lip. Shuichi came not long after, filling her insides with his seed, grunting and panting as he did. Tsumugi’s legs released Shuichi and he pulled out, watching his seed drip from her hole. Tsumugi shivered a bit as she felt it leak, and started to rub her pussy. 

“That was good Sweetchi....very goood.” Tsumugi bit her lip, slowly catching her breath. Shuichi slowly caught his breath and went to lay next to her, looking into her eyes. “You know...I think we still have some time before mom and dad get home. We should probably make the most of it...” Shuichi spoke. Tsumugi smirked and winked. “You’re absolutely right.” With a giggle, Tsumugi brought the covers over them, as they prepared for round two...


End file.
